In seismic exploration in remote and urban areas of the world, acoustic waves are generated at or near the surface and sent downward into the earth. Reflections occur at the interface of the subsurface strata whose acoustic impedances differ, and are subsequently detected by groups of geophones positioned at the earth's surface. Each geophone group (which can comprise a number of individual geophones) produces a composite electrical signal, such signal driving equipment usually located in a recording truck adjacent to the geophones.
Field seismic equipment must be tested. For this purpose, a sinewave generator is often used to drive elements of the field systems in a selected manner. The response of the equipment is a measure of its field worthiness. However, for field testing, such generators should be light-weight, small and portable, and generate a highly accurate sinusoid using preferably a battery power source. No such generator is presently available which meets all of the above-listed requirements.